Monday, June 16, 2008

Discovery of a New Mineral

Until recently the International Mineralological Association recognized 4,324 minerals. Now the tally stands at 4,325. The Astromaterials Research and Exploration Science Directorate at NASA-Johnson Space Center just discovered a new mineral in a very cool place: a particle of cometary dust.

Along with other interplanetary dust particles, or IDP's, it was collected in the stratosphere by an ER-2 high-altitude research aircraft. The dust particle of interest evidently originated in Comet 26P/Grigg-Skjellerup. IMA approved naming the new mineral Brownleeite, in honor of Donald Brownlee at the University of Washington, who founded the field of IDP research. Brownleeite can be synthesized but it's never been found on Earth.

The analytic methods that nailed down the new mineral were extraordinary. Keiko Nakamura-Messenger of ARES used a state-of-the art transmission electron microscope that was installed in 2005 at Johnson Space Center. Exploring a single mote of exotic dust, Nakamura-Messenger and her co-discoverers analyzed chemical composition and crystal structure at nanometer-scale.

NASA announced the discovery last Friday, June 13. Unfortunately, the official press release marginalizes the the significance of the discovery with the headline NASA Finds New Type of Comet Dust Mineral. Variously tweaked versions of the press release now appear on the Web. At astronomy.com you can read fascinating details and quotes (and see how somebody threw in a numerically challenged sub-headline raising the number of IMA-identified minerals to 4,345.) Over at universetoday.com they came up with the titillating headline Alien Mineral From Comet Dust Found in Earth's Atmosphere. Most venues on the Web retain the headline from the official NASA Headquarters press release. A news compilation site called Breitbart.com rephrased it thus: New mineral found in comet dust by NASA team. Much better.

The technical paper announcing the discovery was presented at this year's Lunar Planetary Science Conference (Lunar and Planetary Science XXXIX, paper titled NEW MANGANESE SILICIDE MINERAL PHASE IN AN INTERPLANETARY DUST PARTICLE) with these images from the nano-analysis: